Indirect media flatness measurement

A non-transitory computer readable medium storing a program of instruction which, when executed by a processing device, cause an ink jet printer operative to subject a substrate media to a hold down force during printing to perform a method of media flatness measurement, the method comprising:

• printing a predetermined test image comprising a predetermined pattern having reference points on a substrate media using an ink jet print apparatus to produce a test print;
• and
• comparing the test print with the predetermined test image, including measuring drop placement errors of reference points;
• and
• calculating the height of the substrate media at the location of each reference point based upon the drop placement error.

A printer comprising:

• a media transport operative to receive a substrate media and to convey the substrate media into, through, or out of a printing zone of the printer, the printing zone being an area associated with the printer in which the substrate media is printed with an image;
• a hold-down system operative to generate a hold-down pressure applied to the substrate media in the direction of the first media transport;
• an image capture unit operative to capture an image printed on the substrate media by the printer;
• a controller;
• and
• a non-transitory machine-readable storage medium having a program of instruction thereon, which when executed by the controller causes the printer to
• print a predetermined test image comprising a predetermined pattern having reference points on a substrate media using an ink jet print apparatus to produce a test print;
• and
• compare the test print with the predetermined test image, including measuring drop placement errors of the reference points;
• and
• calculate the height of the substrate media at the location of each reference point based upon the drop placement errors.